With 500 cars said to be added over GT Sport's shelf life, resources aren't being shed that thin. Might as well not include any classic cars. As I'm sure the car industry isn't lacking in 500 up to date cars to choose from. There is one classic car in the first GT(Sting Ray) and three in GT3(Cobra and GT40, GT40 race car). Then again, seeing the Gr.3 Road Cars, PD can easily shave another 20 from that 500.
Maybe PD do a reverse and offer the next DLC as Gr.3/Gr.3 Road Car conversions in the future.
- Gr.3 R32 GT-R & Gr.3 R32 GT-R Road Car(would look like the R32 RM)
- Gr.3 F40, etc.